It was through Propaganda and Silencing of people lead to people denying the fact that the holocaust was happening, and only rumors about concentration camps where among ally troops until they finally liberated them.
The holocaust was the mass genocide of jewish people by the nazi party so the so called "superior" german race could rule over Europe. Nazis beliwved jews were the rats that were investing Europe.
Horace Mann was an educational reformer who lived in the US in the 19th century. He was a first to advocate a system of a public schools and public education as he believed that everyone had a right to education and that it should be free, democratic and have a professionally trained educators who would provide a quality education.
The Sparta, Athens, and other Greek communities collected natural resources to build walls to protect them from external attacks. However, they eventually succumbed to attacks via the ocean route.
